1 VM loses network connection

Jan 18, 2017
97
2
8
39
Hello, i have 2 Proxmox servers (latest versions 4.4) configured into a cluster.
The network on both in Bridge mode.

6 VMs work fine on proxmox server 1
2 VM's work fine on proxmox server 2

But 1 vm dont work fine at server 2.
Ubuntu 16, phmyadmin and apache installed.
His own external IP.

The problem is:
The Ubuntu server loses network connection at a random time.
And this VM server network connection comes up again at a random time. this could be 5 minutes but also 1 hour.
When the network loses connection, i could not connect through SSH from home,
But when i logon on the proxmox VNC, and do: Ping to a website, the connection comes up again.
Looks like a 'sleeping' network connection?


I have installed the prxmox firewall and works fine with the other VM servers.

i disabled the lokal firewall at the VM's.
I allready changed the virtual network adapter from the ubuntu server from virtio to E1000 but no beter result. I rebooted the fysical server.
 

Attachments

  • chart.png
    chart.png
    28.1 KB · Views: 23

manu

Proxmox Staff Member
Mar 3, 2015
806
66
28
Hi Bart
I am not sure here if it is a PVE problem or a routing problem.
Maybe you could try to configure the VM with a different IP address and see if the problem still occurs?
 
Jan 18, 2017
97
2
8
39
Hello Manu, tnx! at this moment i disabled the Proxmox firewall and testing if the problem occurs.
at this moment it goes well for 4 hours ;)

update: damn, losing connection again.
I have asked the provider for a routing check.

but there are no 'sleeping' modes available on ubuntu network connections?
 
Last edited:
Jan 18, 2017
97
2
8
39
Tonight i swap 2 VM's external IP adresses.
And today the same server having the same problem. So, it couldnt be the routing :( (they checked also and coulnt find anything).

Could there be a network driver problem into ubuntu 16?
 

manu

Proxmox Staff Member
Mar 3, 2015
806
66
28
when you say the VM looses network connection as seen from the ouside how do you detect this ? what is doing MRTG in the background ? Ping ? It could be also that the problem comes from your hosting provider.

to debug this a bit, when the VM loses its network connection, can you check inside the VM if the (virtual ) Ethernet link is active :

ip --color link

you see LOWER_UP if the Virtual Ethernet link

if you see LOWER_UP

try to ping an address in your LAN ( another VM, or the gateway )
 
Jan 18, 2017
97
2
8
39
Hello manu, i have a monitoring system (PRTG) from somewhere else. So i know exactly when the problem exist.
I will check ip --color link it when it happen again.
when i ping to a website inside the vm, 2 seconds later (like waking up from sleep modus) ping replys good.

For this moment, I made a backup and restore from the server. For trying.
 
Jan 18, 2017
97
2
8
39
I made 8-2-2017 a backup and restore. 1 day everything went well, but today 2 VM's (on different physical servers) had the same problem.
The vm's were 5 - 20 minutes 'offline' from outside (ping with PRTG). 1 vm server is a production server, so i must fix this problem :(
I was to late behind my pc for checking above options.

so, for now i disabled the proxmox firewall at datacenter level now and waiting if it goes better / good.
:( :( :(
when the problem is : proxmox firewall, i will use again the firewalls from ubuntu VM's.

update: till now (10-02-2017 7:23 AM) no problems. I will wait till the end of this day. fingers crossed.
But if proxmox firewall is a problem.. who could help me?
 
Last edited:

Virtualizer

Active Member
Dec 19, 2011
90
5
28
I will open in short minutes a new thread, why other has equal problems with KVM and exists as other threads! This is very interessting about KVM and routing and firewall - block expl. diferent KVM-machines to communicate from inside to outside!
 

About

The Proxmox community has been around for many years and offers help and support for Proxmox VE, Proxmox Backup Server, and Proxmox Mail Gateway.
We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get your own in 60 seconds.

Buy now!